Researchers at Purdue University have developed a heat pump system that operates at a relatively higher efficiency and a lower cost. This multistage heat pump can utilize two separate methods of heat transfer. Four modes of operation ensure the pump is operating in the most efficient manner for the given set of environmental conditions. The indoor air coil is also designed to fit the target climate and minimizes unnecessary energy consumption. Oil is well managed by a novel technique in the heat pump system. This ensures the compressors are running with the required amount of lubrication and are highly reliable. In addition, the heat pump is designed for manufacturability and is more suitable to produce and maintain. Finally, the whole system is enclosed in a casing, reducing sound. The compressors are acoustically dampened, allowing the residents of a building to enjoy both proper climate control as well as a quiet atmosphere.